Computational Assessment of Bioprosthetic Aortic Valve Function

Overview

Bioprosthetic valves are usually made of biological tissue that are mounted to a frame and are designed to function similarly to a healthy natural valve. Edwards Magna Ease and Intuity Elite bioprosthetic valves have similar leaflets and mounting designs. However, the valves are implanted in the patient in different ways (one is stitched to the wall of the left ventricular outflow tract, and the other is held in place by the radial force of the valve skirt). The study aims to understand in more detail how the different valves interact with the left ventricular outflow tract and aortic root.

The implantation of a bioprosthetic valve is the established surgical technique when replacing the aortic valve to treat various aortic valve diseases. Many different bioprosthetic valves are available. The design and implantation technique in each system would result in different interaction with the left ventricular outflow tract (LVOT) and the aortic root, leading to different flow profiles that may induce platelet aggregation and affect the long-term performance of the bioprosthesis and its durability. Additionally, complications such as valve thrombosis may occur. However, it is not currently clear which bioprostheses/patients are more prone to thrombosis or degradation of the valve. This study aims to develop fluid-structure interaction (FSI) models, which can model blood flow and wall/valve mechanics, using realistic patient-specific geometries and flow conditions which correlate with the true performance of the valve in the imaged patients, and to assess and compare such performances to understand the benefits and challenges with various bioprosthetic valves. FSI models combine computational fluid mechanics (CFD) with structural wall mechanics modelling. This is an alternative approach that allows detailed assessment of flow patterns and estimation of wall shear stress and pressure within blood vessels, and therefore has been applied increasingly to gain better insights into the hemodynamics in cardiovascular diseases

Conditions